Variable valve-timing mechanisms for internal combustion engines are generally known in the art. For example, see U.S. Pat. No. 4,494,495; U.S. Pat. No. 4,770,060; U.S. Pat. No. 4,771,772; U.S. Pat. No. 5,417,186; and U.S. Pat. No. 6,257,186. Internal combustion engines are generally known to include single overhead camshaft (SOHC) arrangements, dual overhead camshaft (DOHC) arrangements, and other multiple camshaft arrangements, each of which can be a two-valve or a multi-valve configuration. Camshaft arrangements are typically used to control intake valve and/or exhaust valve operation associated with combustion cylinder chambers of the internal combustion engine. In some configurations, a concentric camshaft is driven by a crankshaft through a timing belt, chain, or gear to provide synchronization between a piston connected to the crankshaft within a particular combustion cylinder chamber and the desired intake valve and/or exhaust valve operating characteristic with respect to that particular combustion cylinder chamber. To obtain optimum values for fuel consumption and exhaust emissions under different operating conditions of an internal combustion engine, the valve timing can be varied in dependence on different operating parameters.
A concentric camshaft includes an inner camshaft and an outer camshaft. The two camshafts can be phased relative to each other using a mechanical device, such as a cam phaser, to vary the valve timing. Cain phasers require precise tolerances and alignment to function properly. Misalignment between the inner camshaft and the outer camshaft of the concentric camshaft can create problems preventing proper function of the can phaser. It would be desirable to provide an assembly capable of adapting to misalignment between inner and outer camshafts of a concentric camshaft and a can phaser. It would be desirable to provide an assembly capable of accommodating tolerance stack up and thereby resolving binding issues that adversely affect concentric camshaft and phaser system assemblies.
Flexible cable drive systems are generally known, see U.S. Pat. No. 7,717,795; U.S. Pat. No. 7,562,763; U.S. Pat. No. 7,168,123; U.S. Pat. No. 6,978,884; U.S. Pat. No. 5,554,073; U.S. Pat. No. 5,022,876; U.S. Pat. No. 4,911,258; U.S. Pat. No. 4,779,471; U.S. Pat. No. 4,257,192; and U.S. Pat. No. 3,481,156. In a typical rotatable flexible shaft, a wire mandrel has a plurality of layers of closely coiled wire wound there over, each of the layers being successively wound over another in alternately opposing directions, i.e., right or left-hand lay. This shaft is usually covered by a flexible casing, metallic or covered, and a clearance between the shaft and casing is provided in order that the shaft may rotate freely within the casing. These flexible cable drive systems are typically used for light duty power transmission, such as speedometer cables, power seat adjustment, and marine propulsion applications. It would be desirable to provide an assembly capable of adapting to misalignment between inner and outer camshafts of a concentric camshaft and a cam phaser.